CVE-2026-100559 in OpenClaw
Summary
by MITRE • 09/26/2026
OpenClaw versions before 2026.8.1 contain a command parser vulnerability where escaped newlines confuse exec allowlist parsing, allowing hidden commands to execute. Attackers can craft input with escaped newlines to bypass allowlist validation and execute additional commands without expected authorization prompts.
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Analysis
by VulDB Data Team • 09/26/2026
The vulnerability identified in OpenClaw versions prior to 2026.8.1 represents a critical failure in the application's command parsing logic, specifically concerning how escape sequences are processed within input strings intended for execution. This flaw is rooted in an improper neutralization of special elements used by commands and scripts, commonly categorized under CWE-77 as Improper Neutralization of Special Elements used in a Command. The core issue arises when the parser encounters escaped newline characters embedded within user-supplied data. Instead of treating these sequences strictly as literal text or rejecting them based on security policies, the underlying execution engine interprets the escape sequence by splitting the input stream at that point. This behavior fundamentally alters the structure of the command being prepared for execution, creating a discrepancy between what was validated against the allowlist and what is ultimately executed by the operating system shell.
The operational impact of this vulnerability is severe because it directly undermines the security mechanism designed to restrict user actions. OpenClaw utilizes an allowlist approach to permit only specific commands or patterns, relying on strict validation before execution. However, due to the parsing flaw involving escaped newlines, attackers can craft malicious input that appears compliant with the initial validation checks but transforms into a multi-part command upon actual execution. For instance, an attacker might provide a string where the first part matches an allowed command pattern, followed by an escaped newline and then a second, unauthorized command. The allowlist validator sees only the first segment as valid, while the shell interpreter processes both segments sequentially after resolving the escape sequence. This allows hidden commands to execute without triggering expected authorization prompts or security alerts, effectively bypassing access controls that were intended to prevent such actions.
From an offensive perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework, particularly those related to command and script interpretation abuses where attackers leverage parsing ambiguities to inject additional payloads. The ability to execute arbitrary commands without proper authorization can lead to a complete compromise of the host system running OpenClaw. Depending on the privileges under which the application operates, an attacker could escalate privileges, exfiltrate sensitive data, install persistent backdoors, or use the compromised instance as a pivot point for further network attacks. The lack of expected authorization prompts means that security monitoring tools relying on standard authentication logs may fail to detect this initial access vector, allowing the intrusion to proceed undetected until significant damage has occurred.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary and most effective solution is to upgrade OpenClaw to version 2026.8.1 or later, where the command parser has been patched to correctly handle escape sequences without allowing them to alter the execution flow in unintended ways. In environments where upgrading is not immediately feasible, administrators should implement strict input validation at the application layer to reject any input containing newline characters or other control codes before they reach the parsing engine. Additionally, adopting a defense-in-depth approach by running OpenClaw with minimal necessary privileges can limit the impact of successful exploitation. Security teams should also enhance monitoring capabilities to detect anomalous command execution patterns that deviate from baseline behavior, ensuring that even if such bypasses occur in other software components, they are identified and responded to promptly.